1. Field of the Invention
The present invention relates to a chemical compound and an organic light emitting diode (OLED), and more particularly to a 6H-indeno[2,1-b]quinoline derivative and organic light emitting diode using the same.
2. Description of the Prior Art
OLED is composed of organic materials and semiconductor materials. OLED works on the mechanism that electrons and holes diffuse through an electron transport layer (ETL) and hole transport layer (HTL) respectively to enter a light-emitting layer, and recombine in the emitting region to form excitons. When excitons fall to the ground state, the energy is given off in the form of photo radiation. The radiation color can be tuned by applying different emitting materials. OLED has been spotlighted due to a lot of advantages, such as self illumination, wider visual angle (>170°), shorter response time (˜μs), higher contrast, higher efficiency, lower power consumption, higher brightness, lower operative voltage (3-10V), thinner size (<2 mm), flexibility and so on.
Excitons generated from recombining holes and electrons have triplet state or singlet state for its spin state. Singlet exciton relaxation radiates fluorescence and triplet exciton relaxation radiates phosphorescence. Phosphorescence achieves 3-fold efficiency comparing to fluorescence and may greatly enhance the IQE (internal quantum efficiency) of devices up to 100% by adopting metal complexes in electroluminescent configuration to achieve strong spin-orbital coupling and mixing of singlets and triplets. Therefore, phosphorescent metal complexes are now adopted as phosphorescent dopants in the emitting layer of OLED. In addition, by doping proper materials to the light-emitting layer, self-quenching of the host materials can be reduced greatly to enhance the efficiency of the OLED device. With respect to host materials, they must be capable of catching carriers easily and have high photoelectric conversion performance, high thermal stability and proper band gap of singlet state and triplet state.
To sum up, it is an important issue to develop a novel host material to be applied in OLED.